Anatomy the the Heart

The heart is an organ responsible for pumping blood with the blood vessels making use of rhythmic contractions that cardiac muscle.

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Key Takeaways

Key PointsThe love is a four-chambered muscular organ containing an involuntary conduction mechanism that initiates rhythmic contractions to pump blood throughout the body.The heart has actually its own blood supply and is regulated by self-regulating nerve bundles dubbed nodes.The SA and also AV nodes send impulses through the Purkinje yarn that reason muscle contractions come the heart.The love is created of 3 layers: the epicardium (outer layer) which prevents excess development or activity of the heart, the myocardium (middle layer) which initiates contractions steering the cardiac cycle, and the endocardium (inner layer) that lines the cavities and valves.The heart consists of two top chambers referred to as atria and also two lower chambers called ventricles. The left and right sides of the heart room separated by the septum.Valves protect against the backflow the blood and also separate the atria native the ventricle and also the ventricle native the pulmonary artery or aorta.Key Termsheart: A fist-sized muscular body organ in the chest that pumps blood v the body using involuntary contractions that cardiac muscle.ventricle: one of two lower chambers of the heart that receives blood native the atria and also pumps it out into pulmonary or systemic circulation, depending upon side.myocardium: The middle of the 3 layers developing the wall surface of the heart, comprise cardiac muscle tissue. Innervated by the Purkinje fibers.

The human heart is the pump for the circulatory system, and along with the circulatory system is taken into consideration to it is in an body organ of the cardiovascular system. It consists of four chambers and pumps blood v both systemic and pulmonary circulation to enable gas exchange and tissue oxygenation. The love is situated in the thoracic cavity between the lungs and protected by the rib cage.

Structure the the Heart

The heart consists of four chambers separated into two sides. Each side includes an atria i m sorry receives blood into the heart and also flows it into a ventricle, which pumps the blood out of the heart. The atria and also ventricle on every side that the love are attached together through valves that avoid backflow the blood. The wall surface that separates the left and also right side of the heart is referred to as the septum.

The left heart encounters systemic circulation, when the right heart faces pulmonary circulation. The left side of the heart receives oxygenated blood indigenous the pulmonary vein and also pumps it into the aorta, while the right side that the heart receives deoxygenated blood indigenous the vena cava and also pumps it right into the pulmonary vein. The pulmonary vein and aorta likewise have valves connecting them to their respective ventricle.

The heart has its own self-sustaining conduction device that sends out nervous impulses to cardiac tissue. The sinoatrial (SA) and atrioventricular (AV) nodes space bundles the nerve fibers that kind this conduction system. Castle are located in the left atrial wall surface of the heart and send nerve impulses to a large, highly dedicated set of nerves dubbed the Purkinje fibers, which in turn send those nerve impulses to the cardiac muscle tissue. This nodes can send impulses come the heart without central nervous device stimulation, yet may be influenced by nervous stimulation to transform heart rate. The heart also has its very own blood supply, the cardiac arteries that carry out tissue oxygenation come the heart together the blood within the love is not supplied for oxygenation by the heart.

Cardiac Histology

The heart is attached in a double-walled protective membrane referred to as the pericardium, which is a mesothelium tissue of the thoracic cavity. The double membrane the pericardium has pericardial liquid which nourishes the heart and also prevents shock. This composite sac protects the heart, anchors it to neighboring structures, and prevents the heart from overfilling with blood.

The wall of the heart is created of three layers of different tissues. The outer layer is called the epicardium, or visceral pericardium, due to the fact that it is additionally the inner wall surface of the pericardium. The middle layer of the heart, the myocardium, and also contains committed cardiac muscle organization responsible because that contraction. Cardiac muscle organization is distinctive from skeletal or smooth muscle because it pumps involuntarily based on conduction native the AV and also SA nodes. The inner class is dubbed the endocardium and is in call with the blood the the heart pumps. It likewise merges v the inside lining the blood vessels and covers heart valves. Cardiac organization is permanent tissue the does no heal or regenerate as soon as damaged. Together a result, is at risk to scarring and enlargement due to mechanical stress and injury.


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The Mammalian Heart: The position of valves ensures ideal directional flow of blood v the cardiac interior. Keep in mind the distinction in the thickness that the muscled walls of the atrium and the left and also right ventricle.


Key Takeaways

Key PointsThe pericardium is a mesothelium organization of the thoracic cavity which surrounding the heart. The external layer, the fibrous pericardium, is made up of thick connective tissue that protects the heart, anchors it to the surrounding walls, and also prevents that from overfilling.The inner great of the pericardium, the serous pericardium, is further separated into 2 layers, an external parietal layer and an inner visceral layer v the pericardial cavity in in between the 2 layers.The serous pericardium functions to lubricate the heart v pericardial fluid, i beg your pardon is save on computer in the room between the parietal and visceral layers.Pericarditis is inflammation that the pericardium, often because of infection, which have the right to constrict and also put harmful press on the heart.Key Termsfibrous pericardium: composed of dense connective tissue which protects the heart, anchors it to the bordering walls, and prevents the love from overfilling v blood.serous pericardium: located deeper 보다 the fibrous pericardium, this structure has two layers that lubricate the love to stop friction from arising during love activity.pericardium: A serous membrane the surrounds and also protects the heart.

The pericardium is the thick, membranous, fluid-filled sac that surrounds the heart and the roots of the vessels the enter and also leave this an important organ, functioning together a security membrane. The pericardium is just one of the mesothelium tissues of the thoracic cavity, together with the pleura i m sorry cover the lungs. The pericardium is composed of 2 layers, an outer fibrous pericardium and also an inside serous pericardium.


Membranes the the Thoracic Cavity: A transverse ar of the thorax, mirroring the components of the middle and also the posterior mediastinum. The pleural and pericardial cavities space exaggerated because normally over there is no room between parietal and visceral pleura and between pericardium and also heart.


Fibrous Pericardium

The fibrous pericardium is the external layer of the pericardium. The is composed of thick connective tissue which anchors the love to the mediastinum the the chest wall. It avoids the heart from overfilling with blood and also protects the from adjacent infections by completely separating that from the rest of the thoracic cavity. That is consistent with the external fibrous great of the neighboring an excellent blood vessels.

Serous Pericardium

The serous pericardium, the inner class of the pericardium, is composed of two various layers. The outer layer, the parietal layer, is totally adhered to the fibrous pericardium. The inner class is well-known as the visceral layer, which covers and protects the good vessels and also heart. The space between the parietal and visceral class is called the pericardial cavity.

The visceral layer is referred to as the epicardium in the locations where that is in direct call with the heart. The space between these two serous layers, the parietal and the visceral, is the pericardial cavity, which consists of pericardial fluid. The serous pericardium, with its two membranes and the fluid-filled pericardial cavity, offers protection come the heart and also a lubricated sliding surface within i beg your pardon the heart can move in response to its own contractions and also to the movement of nearby structures such together the diaphragm and also the lungs.

Function the the Pericardium

The pericardium is important due to the fact that it protects the love from trauma, shock, stress, and even epidemic from the adjacent lungs. It supports the heart and also anchors it to the medastinum so that doesn’t move within the body. The pericardium lubricates the heart and also prevents it from ending up being too huge if blood volume is overloaded (though it will not protect against chronic love enlargement).

Despite this functions, the pericardium is still fragile to troubles of that is own. Pericarditis is the term because that inflammation in the pericardium, frequently due come infection. Pericarditis is regularly a severe an illness because it deserve to constrict and also apply press on the heart and work against its normal function. Pericarditis come in many types depending on which tissue layer is infected.


Layers that the love Walls

The heart wall surface is consisted of of 3 layers: the outer epicardium, the middle myocardium, and also the inside endocardium.


Learning Objectives

Distinguish in between the epicardium, myocardium, and endocardium class of the heart wall


Key Takeaways

Key PointsThe epicardium is a thin layer of connective tissue and fat serving as secondary layer of defense for the heart. That is considered a continuation of the serous pericardium.The myocardium is the muscle tissue of the heart, composed of cardiac muscle cells dubbed cardiomyocytes that get nervous stimulation from the sinoatrial (SA) and also atrioventricular (AV nodes via the Purkinje fibers.Cardiomyocytes are much shorter than skeletal myocytes, and also contain fewer nuclei. Cardiac muscle is striated.The endocardium is created of endothelial cells that carry out a smooth, non-adherent surface for blood collection and pumping and also may help regulate contractility.An epidemic or inflammation the the endocardium is referred to as infective endocarditis.Key TermsPurkinje fibers: A bundle of nerve fibers located under the endocardium, which supply nervous impulses to the mycardium’s cardiac muscle tissues.endocardium: A thin serous membrane the lines the inner of the heart and valves.cardiomyocyte: A cardiac muscle cell (or myocyte) in the heart, which provides up the cardiac muscle tissue.

The heart wall surface is consisted of of three layers, the epicardium (outer), myocardium (middle), and also endocardium (inner). These tissue layers space highly committed and perform different functions. Throughout ventricular contraction, the wave of depolarization native the SA and AV nodes move from in ~ the endocardial wall through the myocardial layer come the epicardial surface of the heart.

Epicardium


The heart Wall: The wall surface of the love is created of three layers, the thin external epicardium, the thick middle myocardium, and also the an extremely thin inside endocardium. The dark area top top the heart wall is scar from a previous myocardial infarction (heart attack).


The external layer that the heart wall is the epicardium. The epicardium describes both the outer layer of the heart and also the inner class of the serous visceral pericardium, i m sorry is attached to the outer wall surface of the heart. The epicardium is a slim layer that elastic connective tissue and fat the serves as second layer of security from trauma or friction because that the heart under the pericardium. This layer contains the coronary blood vessels, i m sorry oxygenate the tissues of the heart through a blood supply from the coronary arteries.

Myocardium

The middle layer the the heart wall is the myocardium—the muscle tissue of the heart and also the thickest class of the love wall. The is composed of cardiac muscle cells, or cardiomyocytes. Cardiomyocytes are devoted muscle cells the contract like various other muscle cells, however differ in shape. Compared to skeletal muscle cells, cardiac muscle cell are shorter and have actually fewer nuclei. Cardiac muscle organization is additionally striated (forming protein bands) and also contains tubules and gap junctions, unlike skeletal muscle tissue. As result of their continuous rhythmic contraction, cardiomyocytes require a committed blood it is provided to deliver oxygen and also nutrients and remove waste products such as carbon dioxide from the cardiac muscle tissue. This blood it is provided is noted by the coronary arteries.

Endocardium

The inner great of the heart wall is the endocardium, created of endothelial cell that provide a smooth, elastic, non-adherent surface ar for blood collection and pumping. The endocardium may regulate metabolic rubbish removal from love tissues and also act together a obstacle between the blood and also the heart muscle, thus controlling the ingredient of the extracellular fluid in i beg your pardon the cardiomyocytes bathe. This in turn can impact the contractility the the heart.

This tissue likewise covers the valves that the heart and also is histologically constant with the vascular endothelium that the significant blood vessels entering and also leaving the heart. The Purkinje fibers room located simply beneath the endocardium and send nervous impulses indigenous the SA and AV nodes outside of the heart into the myocardial tissues.

The endocardium can end up being infected, a severe inflammatory problem called infective endocarditis. This and also other potential troubles with the endocardium may damages the valves and also impair the normal flow of blood through the heart.


Chambers of the Heart

The love has four chambers. The two atria get blood right into the heart and also the 2 ventricles pump blood right into circulation.


Key Takeaways

Key PointsThe right and also left atria space the peak chambers of the heart and also receive blood right into the heart. The right atrium obtain deoxygenated blood native systemic circulation and also the left atrium receives oxygenated blood indigenous pulmonary circulation.The atria execute not have inlet valves, but are separated from the ventricles by valves. The atria facilitate circulation by permitting uninterrupted blood flow into the heart throughout ventricular systole.The atria have actually several mechanisms in place to ensure the venous blood flow isn’t impaired, such together the absence of valves and the existence of light and brief contractions throughout atrial systole.The best ventricle pumps deoxygenated blood right into pulmonary circulation. The left ventricle pumps oxygenated blood into systemic circulation. The left ventricle is thicker due to the fact that systemic circulation entails a much larger blood volume than pulmonary circulation.Systole explains contraction, as soon as blood is pumped from the heart right into circulation by the ventricles. The can likewise describe atrial systole, in which blood move from the atria to the ventricles throughout ventricular diastole.Diastole describes relaxation, once blood moves into the love while the ventricles prepare come eject that same blood throughout systole.Key Termsdiastole: The relaxation and also dilation of the love chambers in between contractions, during which they fill v blood.systole: The rhythmic convulsion of the heart whereby blood is ejected indigenous one chamber to the next, or the end of the heart and into the arteries.

The heart is the facility pump that the circulatory system, pump blood transparent the body for the purposes of tissue oxygenation and also gas exchange. The heart has four chambers with which blood flows: 2 sets that each form of chamber (atria and ventricles), one per side, each with distinctive functions. The left side of the heart deals with systemic circulation if the ideal side the the heart deals with pulmonary circulation.

The Atria

The atria room chambers in i beg your pardon blood start the heart. Castle are located on the anterior end of the heart, through one atrium on each side. The ideal atrium receives deoxygenated blood from systemic circulation through the remarkable vena cava and also inferior venae cavae. The left atrium receive oxygenated blood indigenous pulmonary circulation v the left and also right pulmonary veins.

Blood passively flows into the atria without passing v valves. The atria relax and dilate (expand) while they fill v blood in a process called atrial diastole. The atria and also ventricles are separated through the mitral and also tricuspid valves. The atria undergo atrial systole, a short contraction of the atria the ejects blood indigenous the atria with the valves and into the ventricles. The chordae tendinae are elastic tendons that attach to the valve indigenous the ventricles and relax throughout atrial systole and ventricular diastole, however contract and close turn off the valve throughout ventricular systole.

One of the defining attributes of the atria is that they perform not impede venous flow into the heart. Atria have four essential qualities that cause them to promote constant venous flow:

There room no atrial inlet valves come interrupt blood flow throughout atrial systole. The venous blood beginning the heart has a very low pressure compared to arterial blood, and valves would require venous blood push to develop up end a long period of time to get in the atria.The atrial systole contractions space incomplete and do no block flow from the veins with the atria into the ventricles. Throughout atrial systole, blood not only empties from the atria come the ventricles, yet continues to circulation uninterrupted from the veins right through the atria into the ventricles.The atrial contractions are slight, preventing far-reaching back push that would impede venous flow.The be sure of the atria is coordinated to begin prior to the begin of ventricular contraction, which likewise helps protect against the love from beating too slowly.

Ventricles

The ventricles are located on the posterior end of the love beneath their matching atrium. The right ventricle receives deoxygenated blood from the ideal atria and also pumps it with the pulmonary vein and also into pulmonary circulation, i m sorry goes right into the lungs because that gas exchange. The left ventricle receive oxygenated blood indigenous the left atria and pumps it with the aorta into systemic circulation to it is provided the organization of the body v oxygen.

The wall surfaces of the ventricles space thicker and stronger 보다 those the the atria. The physiologic pack on the ventricles, i m sorry pump blood throughout the body and lungs, is much better than the pressure generated by the atria to to fill the ventricles. Further, the left ventricle has thicker walls than the right due to the fact that it pumps blood transparent the body, when the ideal ventricle pumps just to the lungs, i m sorry is a lot smaller volume of blood.

During ventricular diastole, the ventricles relax and also fill with blood. During ventricular systole, the ventricles contract, pump blood v the semi-lunar valves into systemic circulation.


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Structure of the heart: framework diagram that a coronal ar of the human being heart indigenous an anterior view. The two bigger chambers space the ventricles.


Key Takeaways

Key PointsFive an excellent vessels enter and also leave the heart: the superior and inferior vena cava, the pulmonary artery, the pulmonary vein, and the aorta.The remarkable vena cava and also inferior vena cava room veins that return deoxygenated blood indigenous circulation in the body and also empty it right into the appropriate atrium.The pulmonary artery dead deoxygenated blood from the right ventricle right into the lungs for oxygenation.The pulmonary veins carry oxygenated blood native the lungs into the left atrium where it is returned to systemic circulation.The aorta is the largest artery in the body. The carries oxygenated blood from the left ventricle that the heart right into systemic circulation.The aorta has many subdivisions that branch off into smaller arteries. This subdivisions are the ascending and also descending aorta, the aortic arch, and the thoracic and ab aorta.Key Termspulmonary arteries: The arteries the take deoxygenated blood far from the best side that the heart and into the capillaries that the lungs because that the function of gas exchange.aorta: The great artery i m sorry carries the blood from the heart into systemic circulation.venae cavae: The two large vessels, the superior and also inferior vena cava, that bring deoxygenated blood from systemic circulation to the heart.

The human circulatory mechanism is a double system, definition there room two different systems that blood flow: pulmonary circulation and systemic circulation. The adult human being heart is composed of two separated pumps, the right side (right atrium and ventricle,) which pumps deoxygenated blood right into the pulmonary circulation, and also the left next (left atrium and ventricle), which pumps oxygenated blood into the systemic circulation. Good vessels space the significant vessels that lug blood into the heart and away from the love to and from the pulmonary or systemic circuit. The an excellent vessels collect and distribute blood across the body from countless smaller vessels.

The Venae Cavae


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The Systemic Circuit: The venae cavae and the aorta type the systemic circuit, i m sorry circulates blood to the head, extremities and abdomen.


The superior and inferior vena cava are collectively called the venae cavae. The venae cavae, in addition to the aorta, room the great vessels associated in systemic circulation. This veins return deoxygenated blood native the body right into the heart, emptying it into the best atrium. The venae cavae room not separated indigenous the appropriate atrium through valves.

Superior Vena Cava

The premium vena cava is a large, quick vein that carries deoxygenated blood native the upper half of the body to the ideal atrium. The right and also left subclavian veins, jugular veins, and also thyroid veins feed into the superior vena cava. The subclavian veins are significant because the thoracic lymphatic duct drains lymph liquid into the subclavian veins, making the premium vena cava a site of lymph liquid recirculation into the plasma. The remarkable vena cava begins over the heart.

Inferior Vena Cava

The worse vena cava is the biggest vein in the body and carries deoxygenated blood native the lower half of the body into the heart. The left and right common iliac veins converge to type the worse vena cava at its lowest point. The worse vena cava begins posterior come the ab cavity and also travels to the heart alongside the abdominal muscle aorta. Follow me the way up the human body from the iliac veins, the renal and suprarenal veins ( kidney and also adrenal glands), lumbar veins (from the back), and hepatic veins (from the liver) all drainpipe into the inferior vena cava.

The Aorta

The aorta is the biggest of the arteries in systemic circulation. Blood is pumped native the left ventricle through the aortic valve into the aorta. The aorta is a highly elastic artery and also is able come dilate and also constrict in solution to blood pressure and volume. When the left ventricle contract to pressure blood through the aortic valve right into the aorta, the aorta expands. This development provides potential energy to aid maintain blood pressure during diastole, as soon as the aorta passively contracts. Blood pressure is greatest in the aorta and diminishes through circulation, getting to its lowest points in ~ the finish of venous circulation. The difference in pressure between the aorta and also right atrium accounts because that blood flow in the circulation, together blood operation from locations of high push to locations of short pressure.

Components the the Aorta

The aortic arch contains peripheral baroreceptors (pressure sensors) and chemoreceptors (chemical sensors) the relay information worrying blood pressure, blood pH, and also carbon dioxide level to the medulla oblongata of the brain. This details is handle by the brain and the autonomic nervous system mediates the homeostatic responses that involve feedback in the lungs and also kidneys. The aorta extends approximately the heart and travels downward, diverging into the iliac arteries. The five components of the aorta are:

The ascending aorta lies in between the heart and also the arch the aorta. It breaks off into the aortic sinuses, several of which kind the coronary arteries.The arch the aorta is the top of the aorta, which division off right into the left carotid artery, brachiocephalic trunk, and also the left subclavian artery.The to decrease aorta is the ar from the arch of aorta to the point where the divides into the common iliac arteries. It is subdivided right into the thoracic and abdominal aorta.The thoracic aorta is the part of the diminish aorta above the diaphragm. That branches off right into the bronchial, mediastinal, esophageal, and also phrenic arteries.The abdominal aorta is the part of the diminish aorta below the diaphragm, i m sorry divides into the iliac arteries and also branches into the renal and also suprarenal arteries. This part of the aorta is delicate to bursting and hemorrhage (aneurysm) native persistently high blood pressure.

The Pulmonary Arteries

The pulmonary arteries carry deoxygenated blood native the best ventricle right into the alveolar capillaries the the lungs to unload carbon dioxide and take up oxygen. These are the just arteries that carry deoxygenated blood, and also are considered arteries due to the fact that they bring blood away from the heart. The short, wide vessel branches right into the left and right pulmonary arteries that provide deoxygenated blood to the respective lungs. Blood very first passes through the pulmonary valve as it is ejected into the pulmonary arteries.


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Pulmonary circuit: chart of pulmonary circulation. Oxygen-rich blood is shown in red; oxygen-depleted blood in blue.


The Pulmonary Veins

The pulmonary veins lug oxygenated blood indigenous the lungs to the left atrium the the heart. Despite carrying oxygenated blood, this an excellent vessel is still thought about a vein due to the fact that it carries blood in the direction of the heart. Four pulmonary veins enter the left atrium. The ideal pulmonary veins happen behind the ideal atrium and also superior vena cava when the left happen in former of the descending thoracic aorta. The pulmonary arteries and also veins space both considered part of pulmonary circulation.


Myocardial Thickness and Function

The myocardium (cardiac muscle) is the thickest section of the heart wall surface and has cardiomyocytes, the contractile cell of the heart.


Key Takeaways

Key PointsCoordinated convulsion of cardiomyocytes reasons the love to contract and expel blood right into circulation.The myocardium is thickest in the left ventricle, as the left ventricle must create a the majority of pressure to pump blood into the aorta and also throughout systemic circulation.Cardiac muscle has a high thickness of mitochondria and a large blood supply, which keep it to work continuously.Sarcomeres room the simple unit of muscle tissue, composed mainly of actin and myosin myofibrils.The heart’s thickness may adjust over time and adapt come compensate for diseases, which regularly results in heart failure.Key TermsCardiac hypertrophy: an adaptive an illness in i m sorry the wall surfaces of the heart come to be too special to pump blood effectively. That is typically a complication that hypertension.sarcomere: The straightforward contractile unit the contractile muscle, which has myofibril filaments made out of myosin and also actin, the 2 proteins the slide previous one one more to reason a muscle contraction.cardiomyocyte: A cardiac muscle cell (myocyte) in the heart.

The myocardium, or cardiac muscle, is the thickest section of the heart wall and includes cardiomyocytes, the contractile cells of the heart. As a form of muscle tissue, the myocardium is unique amongst all various other muscle tissues in the human body. The thickness of the myocardium identify the stamin of the heart’s capacity to pump blood.

Myocardial Histology

The structure of cardiac muscle shares some features with bones muscle, yet has countless distinctive features of that is own. Cardiomyocytes are much shorter than bones myocytes and have under nuclei. Every muscle fiber connects come the plasma membrane (sarcolemma) v distinctive tubules ( T-tubule ). At these T-tubules, the sarcolemma is studded v a big number that calcium channels which allow calcium ion exchange in ~ a rate much much faster than that of the neuromuscular junction in skeletal muscle. The flux that calcium ions right into the muscle cells reasons stimulates an action potential, which causes the cell to contract.

Cardiac muscle, choose skeletal muscle, is made up of sarcomeres, the basic, contractile devices of muscle. Sarcomeres space composed of long, fibrous proteins that slide past each other as soon as the muscles contract and also relax. Two of the necessary proteins found in sarcomeres room myosin, which forms the thick filament, and actin, which develops the slim filament. Myosin has actually a long, fibrous tail and a globular head that binding to actin. The myosin head additionally binds to ATP, the source of power for cellular metabolism, and is required for the cardiomyocytes to sustain us and function normally. Together, myosin and actin type myofibril filaments, the elongated, contractile threads uncovered in muscle tissue. Cardiac muscle and also skeletal muscle both save the protein myoglobin, which stores oxygen.

Cardiac muscle is adjusted to be extremely resistant to fatigue. Cardiomyocytes have a huge number the mitochondria, enabling consistent aerobic respiration. Cardiac muscle also has a big blood supply loved one to its size, which provides a continuous stream of nutrients and also oxygen while providing ample removed of metabolic waste.


Cardiac Muscle: The tissue structure of cardiac muscle consists of sarcomeres that room made that myofibrils through intercalated disks, that contain cardiomyocytes and have plenty of mitocondria.


Myocardial Thickness

The myocardium has variable level of thickness within the heart. Chambers the the heart with a thicker myocardium space able to pump blood with an ext pressure and force contrasted to chambers the the heart v a diluent myocardium. The myocardium is thinnest in ~ the atria, as these chambers primarily fill with passive blood flow. The ideal ventricle myocardium is thicker 보다 the atrial myocardium, together this muscle should pump every blood return to the heart into the lungs for oxygenation. The myocardium is thickest in the left ventricle, together this chamber must create comprehensive pressure to pump blood into the aorta and throughout systemic circulation.

The thickness the the myocardium may adjust in some people as a compensatory adaptation to disease, one of two people thickening and becoming stiff or becoming thinner and flabby. Cardiac hypertrophy is a common result of hypertension (high blood pressure) in which the cell of the myocardium enlarge together an adaptive response to pumping versus the greater pressure. Eventually, hypertrophy may come to be so severe that heart failure occurs as soon as the love becomes for this reason stiff the it deserve to no much longer pump blood. A flabby love is frequently the an outcome of myocardial infections, in i beg your pardon the love muscle becomes so weak that it cannot properly pump blood, which additionally leads to heart failure.


Right Ventricular Hypertrophy: If the heart adapts to become too thick, it will certainly not be able to pump blood as efficiently, and also heart failure might occur.


Key Takeaways

Key PointsThe cardiac skeleton consists of 4 bands of dense connective tissue, dubbed fibrous rings, that surround the base of the pulmonary trunk, aorta, and mitral and tricuspid valves.The love ‘s fibrous skeleton stops the circulation of electric currents between the chambers the the heart so the it only flows with the atrioventricular (AV) bundle. This causes a delay in depolarization so that the ventricles contract after castle fill v blood.The AV bundle is a bundle the electrically-connected cardiomyocytes the transmit impulses native the AV node come the apex the the heart. It is situated in the center of the cardiac skeleton.The cardiac skeleton is composed mainly of the protein collagen, a glycoprotein uncovered in every connective tissues.Key Termscollagen: A glycoprotein that develops elongated fibers, usually uncovered in the extracellular procession of connective tissue.fibrous rings: Four dense bands of difficult elastic tissue that encircle the bases the the valves of the heart.

The cardiac skeleton, or fibrous skeleton of the heart, is the structure of dense connective organization that the end the atria from the ventricles. The fibrous skeleton provides an important support because that the heart and also separates the flow of electric impulses through the heart.

Fibrous Ring Structure


Fibrous ring of the Heart: Transverse ar of the heart mirroring the fibrous rings bordering the valves.


The major structure that cardiac skeleton is composed of four thick bands of tough elastic tissue dubbed fibrous rings that encircle the bases that the love valves. The fibrous skeleton is composed primarily of collagen, a protein found in every kind of connective tissue in the human being body. Over there are four fibrous rings:

The aortic ring encircles the aortic valve. It provides support for the aortic valve so the it is open, yet does not have actually backflow.The pulmonary ring encircles the pulmonary valve. Similar to the aortic ring, it gives structural assistance for the pulmonary valve.The left fibrous ring encircles the bicuspid valve. This ring is the thickest and also strongest of all the fibrous rings due to the thickness that the left ventricle, which requires more structural support than the other chambers that the heart. It also surrounds the coronary arteries and AV node.The best fibrous ring encircles the tricuspid valve. It likewise surrounds the coronary arteries and also AV node.

The fibrous skeleton provides a an excellent amount that structural and functional support for the valves the the love by permitting them to continue to be open and also provides a point of attachment because that the valves to the wall surface of the heart.

Electrical Functions

The fibrous skeleton the the heart acts together an insulator because that the flow of electric current across the heart. It stops the flow of electricity in between the various chambers of the love so that electrical impulses execute not circulation directly between the atria and also ventricles. The sinoatrial (SA) node lies on the top of the heart, while the AV node is situated at the facility of the fibrous skeleton, the just path through which electricity can circulation through the heart.

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This electrical separation is important for cardiac function, because electrical impulses circulation from the top of the heart to the bottom the the heart. The separation enables the AV node and AV bundle to hold-up the wave of depolarization so that the atria have the right to contract and assist in ventricular filling before the ventricles us depolarize and contract. Without the fibrous skeleton the the heart, the heart’s capability to pump blood would be significantly less efficient since the ventricles would contract before filled to capacity. The fibrous skeleton the the heart likewise protects against cardiac arrhythmias.